Open Science (OS) is a global movement reflecting in the scientific community a growing awareness of the importance of transparency and sharing. It promises to be a victory for cooperation over competition. However, to succeed, it will have to overcome a deep human instinct of competitiveness. This inclination is fostered by an evaluation method based essentially on competition. It is very difficult today for early career researchers to adhere to the principles of OS as long as they keep being evaluated according to metric criteria that are most often indirect and reflect more the publisher’s prestige than the candidates’ qualities. Being trained and judged like jockeys in a horse race does not encourage them to take the time necessary for serenity in their research process nor to exchange and share honestly with their peers. A qualitative multi-criteria approach, OS-CAM: Open Science Career Assessment Matrix is now proposed. It is based not only on scholarly productivity but also on qualities expected in OS. It is adjustable according to the career level and to the field of research. It awaits to be used globally and fairly.